This project will develop a light-weight, Real-Time meter for determining carbon dioxide concentration and total exhalant flux for (human) respiration research and clinical applications. Currently available analyzers are extremely large, uncomfortable and are not portable. Exploiting recent advances in infrared instrumentation and electronic packaging technology, we propose a compact (cm size) integrated unit which monitors carbon dioxide content and total exhalant flow. Compared to existing designs which use separate carbon dioxide and flow volume sensors, the proposed sensor would be very precise, small, self contained, and portable, thus enabling more detailed measurements in a variety of environments. In Phase I, we will fabricate sensor assemblies according to a test matrix of different component designs and configurations. We will evaluate these assemblies by using conventional benchtop equipment to measure system sensitivity, speed, repeatability, and stability. We will calibrate the benchtop monitor against standard laboratory IR instruments using a standard gas cell and a calibrated pneumotachograph. This will establish maximum practical repetition rates and sensitivity for the device. In Phase II we will iteratively refine the design and fabricate several working prototypes. A successful development program will result in a sensitive measurement system which will eliminate the restrictions of the current technology, thereby revolutionizing respiration monitoring and research. PROPOSED COMMERCIAL APPLICATIONS The proposed monitor will provide an immediate measurement of carbon dioxide presence and simultaneous determination of total exhalant volume. This will supply valuable patient information in a variety of clinical and research settings. It could also find use in athletic training and critical care applications.